> Source: [sk164356](https://support.checkpoint.com/results/sk/sk164356)

# sk164356 - SIP phones behind SMB appliances fail to pull contacts from the external PBX

| Property | Value |
|----------|-------|
| Solution ID | sk164356 |
| Date Created | 2019-12-29 |
| Last Modified | 2023-07-19 |
| Technical Level | General |
| Products | Spark Firewall (Locally Managed) |
| Versions | R81.10.X |
| Platform | 1500, 1600, 1800, 910 |

## Symptoms

- * SIP phones behind SMB appliances fail to pull contacts from the external Private Branch Exchange (PBX) to which they are registered.

* These are the kernel drops for the applicable packets: `fw_log_drop_ex: Packet proto=17 x.x.x.x:5060 - > y.y.y.y:5060 dropped by `fw_early_sip_nat Reason: failed to get SIP header;

  where:
  * `x.x.x.x` is the external PBX IP
  * `y.y.y.y` is the SIP phone IP

  <br />

* If SIP inspection is disabled (less secure), the SIP phones pull the contacts but drop the calls after 15 minutes.

## Solution

[Contact Check Point Support](https://www.checkpoint.com/support-services/contact-support/) to get a Hotfix for this issue.   
A Support Engineer will make sure the Hotfix is compatible with your environment before providing the Hotfix.   
For faster resolution and verification please collect [CPinfo](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk92739) files from the Security Management and Security Gateways involved in the case.

---

# Agent Instructions

This content is from the Check Point Support Center (https://support.checkpoint.com), the official knowledge base for Check Point cybersecurity products.

## Navigating This Knowledge Base

- **Complete index**: [llms.txt](https://support.checkpoint.com/llms.txt)
- **All SK articles**: [SecureKnowledge Sitemap](https://support.checkpoint.com/sitemaps/secureknowledge-sitemap-index.xml)
- **SK article URL pattern**: `https://support.checkpoint.com/results/sk/{skId}`
- **Markdown responses**: AI bot User-Agents automatically receive `text/markdown` content